Aircraft often include one or more control surfaces such as, for example, one or more horizontal stabilizers. The horizontal stabilizer may be located, for example, at the rear of the aircraft and may include elevator control surfaces that are attached that may be used to change the pitch of the aircraft. A Horizontal Stabilizer Trim Actuator (HSTA) may be used to move the horizontal control surface. The HSTA may be, for example, a hydraulic system that may actuate the horizontal control surface responsive to commands issued by a controller or pilot of the aircraft.
In certain examples, the horizontal control surface may be moved to alleviate load on the elevator control surfaces. In such examples, un-commanded or unintended movement of the horizontal stabilizer may not be desirable. As such, a HSTA designed to prevent such un-commanded or unintended movement is desirable.